It shall be a breach of ethical standards for any former employee to engage in selling or attempting to sell supplies, services, or construction to LBJ for six months following the date employment ceased. The term “sell” as used herein means signing a bid, proposal, or contract; negotiating a contract; contacting any employee for the purpose of obtaining negotiating, or discussing changes in specifications, price, cost allowances, or other terms of a contract; settling disputes concerning performance of a contract; or any other liaison activity with a view toward the ultimate consummation for a sale although the actual contract therefore is subsequently negotiated by another person; provided, however, that this subsection is not intended to preclude a former employee from accepting employment with private industry solely because the former employee’s employer is a contractor with LBJ, nor shall a former employee be precluded from serving as a consultant to LBJ.